Bug 2476813 (CVE-2026-44240)

Summary:	CVE-2026-44240 basic-ftp: basic-ftp: Client-side Denial of Service via unterminated multiline FTP responses
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	abarbaro, alizardo, bbrownin, caswilli, dschmidt, erezende, jchui, jhe, jkoehler, jlanda, kaycoth, kshier, ktsao, lphiri, nboldt, oaljalju, psrna, rhel-process-autobot, simaishi, smcdonal, stcannon, teagle, watson-tool-maintainers, yguenane
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in basic-ftp, an FTP client for Node.js. A malicious or compromised FTP server can exploit this vulnerability by sending an unterminated multiline response during the initial FTP banner phase, before authentication. The client continuously appends attacker-controlled data and repeatedly reparses the accumulated buffer without enforcing a maximum size. This can lead to a client-side Denial of Service (DoS), causing the application to become unresponsive, consume excessive memory and CPU, and potentially result in process termination or service degradation.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2501306
Bug Blocks:

Description OSIDB Bzimport 2026-05-12 21:02:49 UTC

basic-ftp is an FTP client for Node.js. Prior to 5.3.1, basic-ftp is vulnerable to client-side denial of service when parsing FTP control-channel multiline responses. A malicious or compromised FTP server can send an unterminated multiline response during the initial FTP banner phase, before authentication. The client keeps appending attacker-controlled data into FtpContext._partialResponse and repeatedly reparses the accumulated buffer without enforcing a maximum control response size. As a result, an application using basic-ftp can remain stuck in connect() while memory and CPU usage grow under attacker-controlled input. This can lead to process-level denial of service, container OOM kills, worker restarts, queue backlog, or service degradation in applications that automatically connect to FTP endpoints. This vulnerability is fixed in 5.3.1.